In the manufacturing of integrated circuits (ICs), devices are formed on a wafer and connected by conductive interconnection layers. These conductive interconnection layers are created by first forming openings (e.g. trenches and via holes in a dielectric layer) and then filling these openings with a conductive material.
In general, a conductive material is formed within the openings by an electrochemical plating process (ECP process). First, a seed layer is formed within the openings. Then the remaining spaces of the openings are filled with a conductive material. Finally, a planarization process is performed to remove excess material.